Desulfobulbaceae bacteria were recently discovered to form centimeter-long cables, containing thousands of cells that share an outer membrane. They live in the ocean floor where the deeper cells do not have access to the oxygen in the upper layers of sediment. The deeper cells do, however, have access to hydrogen sulfide, which the bacteria oxidize to gain electrons. The electrons then travel up through the shared periplasmic space of the bacterial cable where the cells closer to the sediment surface can use them to reduce oxygen molecules and generate energy.